1. Field of the Invention
The present invention relates to a transfer device equipped with feed bars having fingers for gripping an end part of a blank. The present invention also relates to a transfer device equipped with cross bars having a blank attachment member.
2. Description of the Related Art
For transfer devices having a feed bar placed in the blank transfer direction, the typical method of transfer is to grasp the end part of a blank material with a clamping motion of a pair of feed bars that are arranged parallel to each other. For example, the operation can be conducted at an approximate stroke of 45 times per minute. However, as the front-back measurement of the blank material becomes larger (for example, 1,300 mm or greater) there is sagging of the center portion of the blank material because the blank material loses rigidity. Transfer is especially difficult in the steps prior to the processing the blank material, e.g. bending or the like.
With large blank materials (for example, blank materials of 2,500 mm or greater), there is the cross-bar method in which transfer occurs by having a blank attachment member that attaches to the upper surface of the blank material. With a lifting and lowering motion, after attaching to the blank material, the cross bars transfer the blank material to the next stage. The cross-bars are held in a position that does not interfere with the die during processing, and after the processing, they return to the previous stage to transport the next blank material.
For the cross-bar method as described above, a large amount of time is needed for the motions for one cycle, and as a result, the mechanical device averages only 10 strokes per minute. Compared to the transfer by the previously described fingers, the productivity is reduced. Furthermore, a driving device for moving the cross bars must be provided on the feed bars. As a result, the mechanical device becomes large.
Thus, there is still a need in the art to develop a transfer device that can move large blank materials at a high rate of speed and is of a compact size.
It is the foregoing and various other drawbacks of the prior art which the present invention seeks to overcome by providing a transfer device that has high productivity and is compact.
The present invention uses cross bars that have a blank attachment member and that are suitable for transferring large blank materials that, prior to processing, do not have rigidity, sag in the center and are difficult to transport. Additionally, the present invention also jointly uses fingers that are suitable for rapid transport of blank materials that, after processing, are molded and have rigidity.
The transfer device of the present invention has a construction in which two types of transfer devices are jointly used. These two types are cross bars that have a blank attachment member and fingers for gripping the blank end parts. The invention is a transfer device having a pair of parallel arranged feed bars.
Two types of transferring devices are used concurrently. One type of transferring device is cross bars that span the feed bars and that have a blank attachment member and are used for transferring a blank material, which has been brought to an idle stage of the transfer device, to a next stage. A second type of transferring device is fingers for gripping blank end parts and are used for each downstream stage from the second stage and beyond the feed bars. Further, the transfer device may include a rack formed in a center portion of the pair of cross bars. One of the facing ends of cross bars are fixed on guides, which are affixed to the upper surfaces of the feed bars, and the other ends are slidably guided. In addition, a pinion is rotatably provided on a plate that is joined near the center part of the cross bars, and the pinion meshes with the rack to construct a rack-pinion mechanism.
The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of a specific embodiment thereof, especially when taken in conjunction with the accompanying drawings wherein like reference numerals in the various figures are utilized to designate like components, and wherein: